As the critical dimensions for semiconductor devices continue to shrink, there is an increased need for semiconductor process equipment that can uniformly process semiconductor substrates. One instance of where this need may arise is in controlling the flow of process gases proximate the surface of a substrate disposed in a process chamber. The inventors have observed that, in conventional process chambers that utilize a single pump to exhaust process gases from a side of the process chamber, process non-uniformities (for example, non-uniform etch rates and/or non-uniform critical dimensions) exist that are believed to be due, at least in part, to non-uniform asymmetric flow of process gases in the process chamber. In addition, the inventors have further observed that such an asymmetric flow of process gases may further cause plasma non-uniformities.
Thus, the inventors have provided an improved apparatus for processing substrates.